Yellow gums in a cat mean bilirubin is circulating where it should not be, and in cats the list behind that is short enough to work through in one visit. Look at the sclera in daylight first, then the inside of the ear flap. If both are yellow, total bilirubin is above 2 mg/dL and the cat needs bloodwork today, not a wait-and-see week.
Check the sclera first, then the ear
Do it in daylight or under a bright white lamp. Warm indoor bulbs and yellow LEDs make a normal cat look jaundiced, and a phone flashlight in a dim room is worse. The sclera is the thin membrane around the eyeball, easiest to see by lifting the upper lid slightly. The inner surface of the pinna shows color even in cats with dark fur on the face.
Gums and the hard palate work too, but pale pink gums are anemia, not jaundice, and the two look alike at 8 p.m. in a kitchen. Yellow under the chin, on the abdomen, or inside the ears is late: bilirubin is usually over 5 mg/dL by then. Long-haired cats hide it for 1 to 2 weeks.
Bilirubin above 2 mg/dL is what you are seeing
Normal total bilirubin in a cat is roughly 0.1 to 0.5 mg/dL. Tissue color shifts at about 2 mg/dL, becomes obvious between 2 and 4, and is hard to miss above 5. That gap matters: a cat can be seriously ill at 1.2 mg/dL with a normal-looking eye, and a cat at 3 mg/dL may still eat and jump onto the counter.
Urine is the earlier signal. Unlike dogs, healthy cats do not put bilirubin into urine, so a positive dipstick is abnormal at any level and often appears 24 to 48 hours before the eye turns yellow. Ask for the urinalysis even when the bill is already high.
Three buckets, three different emergencies
Prehepatic jaundice is a red cell problem: cells are destroyed faster than the liver can process the hemoglobin. Immune-mediated hemolytic anemia, Mycoplasma haemofelis, FeLV, Heinz body anemia from onion, garlic, acetaminophen, zinc, or propofol, and less often Babesia. These cats are anemic and yellow at once, and packed cell volume can fall from 35 percent to 15 percent in 2 to 3 days.
Hepatic jaundice is the liver failing to conjugate and excrete. Cholangitis and cholangiohepatitis are common in cats and often travel with inflammatory bowel disease and pancreatitis as triaditis. Add hepatic lipidosis after 3 to 5 days of not eating, liver lymphoma, lily and acetaminophen toxicity, and end-stage cirrhosis.
Post-hepatic jaundice is plumbing: the bile duct is blocked by pancreatitis, a gallstone, a mass at the duodenal papilla, or a stricture. Bilirubin climbs fast and high, often past 10 mg/dL in a week, and the enzyme pattern flips: alkaline phosphatase in the thousands with only a modest ALT.
| Pattern | Total bilirubin (mg/dL) | ALT (U/L) | ALP (U/L) | PCV (%) | Urine bilirubin |
|---|---|---|---|---|---|
| Hemolytic | 2-6 | 100-300 | 100-200 | 12-20 | Negative to 1+ |
| Hepatic, inflammatory | 2-10 | 200-500 | 200-800 | 25-40 | 2+ to 3+ |
| Hepatic, lipidosis | 3-8 | 150-400 | 300-900 | 35-45 | 1+ to 2+ |
| Post-hepatic obstruction | 8-20 | 100-400 | 1500-6000 | 30-45 | 2+ to 3+ |
| Reference range | 0.1-0.5 | 20-100 | 10-90 | 30-45 | Negative |
When a cat has not eaten for 3 days
A cat that stops eating for 3 to 5 days mobilizes fat to the liver faster than the liver can export it, and the fat parks in hepatocytes. Overweight cats, body condition score 7 or higher out of 9, are the classic cases, and any illness that kills appetite can start it: pancreatitis, dental pain, kidney disease, a new pet in the house.
The usual picture is 10 percent body weight loss over 2 to 3 weeks, yellow sclera, and an ultrasound that finds no obstruction. Left alone, these cats can go from eating normally to moribund in 7 to 10 days, which is why appetite is a clinical measurement and not a personality trait.
The feeding tube decision
Most internists set the tube decision at 3 to 5 days of true anorexia, sooner if bilirubin is rising and the cat has lost 10 percent of body weight. Waiting a week to see if appetite returns costs more than the tube: lipidosis cats fed inside the first 5 days survive noticeably better than cats fed after 10 days.
Calories start low. Resting energy requirement is about 70 times body weight in kilograms to the 0.75 power, which is 200 to 220 kcal per day for a 4 kg cat. Feed 50 to 60 percent of that for the first 24 to 48 hours, reach full intake by day 3 or 4, and split it into 3 to 4 meals given over 10 to 15 minutes each.
A nasoesophageal tube takes 5 minutes to place and works for 5 to 7 days; an esophagostomy tube needs brief anesthesia but lasts months and is the usual choice for lipidosis. Placement is confirmed on a radiograph before the first meal, and the stoma is checked daily for 3 days. Electrolytes, especially potassium and phosphorus, get rechecked at 24 and 72 hours because refeeding moves them fast.
What happens in the first 24 hours
Bloodwork means a full chemistry panel, CBC with a reticulocyte count, T4, and urinalysis, plus FeLV and FIV status. Abdominal ultrasound does more than plain films: it shows bile duct dilation, gallbladder sludge, pancreatic swelling, and liver texture, and it usually answers the obstruction question in 15 minutes.
If the cat is anemic and yellow, add a blood smear read by a pathologist and a Coombs test. Vitamin K1 at 1 to 2.5 mg is given before biopsy or surgery when clotting times are prolonged, and a biopsy is postponed until the cat is stable enough to survive it.
Yellow is not always bilirubin
Carotenoids in food can tint a cat, and pale gums with normal bilirubin is anemia, not liver disease. Cats with pancreatitis can turn yellow from duct compression alone, which is why the pancreatitis workup runs alongside the liver panel. A cat that chewed a lily, licked onion soup, or swallowed a zinc penny is a poisoning case, and the toxin list comes before anesthesia, biopsy, or a feeding tube.
Five steps for the next 24 hours
- Photograph the eye and the ear in daylight, then repeat the photo in 12 hours so the change is measurable.
- Weigh the cat on a kitchen scale, in grams, and write the number down. A 4 kg cat losing 400 g has lost 10 percent.
- Book bloodwork, urinalysis, and an abdominal ultrasound for the same day, and ask for FeLV and FIV status.
- Stop all supplements and human medications, and bring every package, including flea products.
- If the cat has eaten nothing for 72 hours, ask directly whether a feeding tube should go in now.
Frequently asked
How quickly does jaundice appear in a cat?
Faster than most owners expect once bilirubin passes 2 mg/dL, but the visible change can lag the disease by days. Urine bilirubin often turns positive 24 to 48 hours before the sclera does, and a cat with a rising bilirubin can look normal in the morning and clearly yellow by evening under daylight.
Is jaundice in cats always liver disease?
No, and that is the main reason for the lab work. Roughly a third of cases are hemolytic, meaning the red cells are being destroyed, and another group is post-hepatic with a blocked bile duct. The ALT, ALP, PCV, and urine bilirubin pattern separates the three groups before any biopsy is planned.
Will a cat with hepatic lipidosis recover?
Most do when fed early and treated for the underlying cause. Survival with a feeding tube is commonly reported at 60 to 80 percent, and cats fed inside the first 5 days do better than cats fed after 10. Recovery takes 3 to 6 weeks of tube feeding, with weekly weight and bilirubin checks.